The present invention relates to smokable and/or combustible material, and in particular to processes for providing such material by the pyrolysis of tobacco material.
Popular smoking articles, such as cigarettes, have a substantially cylindrical rod shaped structure and include a charge of smokable material, such as shreds of strands of tobacco material (i.e., in cut filler form), surrounded by a paper wrapper, thereby forming a tobacco rod. It has become desirable to manufacture a cigarette having a cylindrical filter element aligned in an end-to-end relationship with the tobacco rod. Typically, a filter element includes cellulose acetate tow circumscribed by plug wrap, and is attached to the tobacco rod using a circumscribing tipping material. Many cigarettes include processed tobacco materials and/or tobacco extracts in order to provide certain flavorful characteristics to those cigarettes.
Many types of smoking products and improved smoking articles have been proposed through the years as improvements upon, or as alternatives to, the popular smoking articles. Recently, U.S. Pat. No. 4,708,151 to Shelar; U.S. Pat. No. 4,714,082 to Banerjee et al.; U.S. Pat. No. 4,756,318 to Clearman et al.; U.S. Pat. No. 4,793,365 to Sensabaugh, Jr. et al.; 4,917,128 to Clearman et al.; U.S. Pat. No. 4,938,238 to Barnes et al.; U.S. Pat. No. 4,928,714 to Shannon; U.S. Pat. No. 4,893,639 to White; and U.S. Pat. No. 4,827,950 Banerjee et al.; and European Patent Publication Nos. 212,234 and 277,519 propose cigarettes and pipes which comprise a fuel element, an aerosol generating means physically separate from the fuel element, and a separate mouth-end piece. Such types of smoking articles are capable of providing natural tobacco flavors to the smoker thereof by heating without necessarily burning tobacco in various forms.
There has been interest in smokable and combustible tobacco material other than conventionally processed tobaccos. For example, several patents have proposed the production of smokable materials having a high carbon content. These include U.S. Pat. No. 2,907,686 to Siegel, U.S. Pat. No. 3,738,374 to Bennett, U.S. Pat. No. 3,885,574 to Borthwick et al, U.S. Pat. No. 3,943,941 and U.S. Pat. No. 4,044,777 to Boyd et al., U.S. Pat. No. 4,002,176 to Anderson et al. U.S. Pat. No. 4,019,521 and U.S. Pat. No. 4,133,317 to Briskin, U.S. Pat. No. 4,219,031 to Rainer, U.S. Pat. NO. 4,286,604 to Ehretsmann et al., U.S. Pat. No. 4,326,544 to Hardwick et al., U.S. Pat. No. 4,481,958 to Rainer et al., U.S. Pat. No. 4,244,381 to Lendvay U.S. Pat. No. 4,256,123 to Lendvay et al, U.S. Pat. No. 4,771,795 to White et al. and U.S. Pat. No. 4,920,990 to Lawrence et al. and Great Britain Patent Nos. 956,544 to Norton and 1,431,045 to Boyd et al., and European Patent Application No. 117,355 to Hearn, et al and No. 236,992 to Farrier et al. In addition, U.S. Pat. No. 3,738,374 to Bennett proposes that tobacco substitutes may be made from carbon or graphite fibers, mat or cloth, most of which are made by the controlled heating of various cellulosic materials.
It would be highly desirable to alter the character of tobacco material by pyrolyzing extracted tobacco material to form a pyrolyzed material. The pyrolyzed material can be used as a smokable and/or combustible tobacco material in various smoking articles.